Method of disintegrating



Patented Oct. 23, 1934 METHOD OF DISINTEGRATING Thomas Robinson, NewYork, N. Y., assignor to Lancaster Processes, Inc., New York, N. Y., acorporation of New York Application October 30,

14 Claims.

This invention relates 'to disintegration of fibrous materials for thepurpose of reducing them to a pulp suitable for use in making paper,paper board, and various other products. More particularly, theinvention is concerned with a novel method of breaking down fibrousmaterials to free the fibres, which may be carried on as a continuousoperation and without interruption, fresh stock being continuously addedto, the supply undergoing treatment and pulp of substantially uniformcharacteristics being continually withdrawn therefrom during thepractice of the method.

The method of my invention is especially suited for the treatment ofpaper stock and the application of the method to the pulping of thatmaterial will presently bedescribed in detail, though it is to beunderstood that the utility of the invention is not restricted to anyspecific material but it' may be used for distintegrating and pulpingmany other fibrous materials including natural 'products, such asgrasses, peat, woody' materials, and the like. v

In general, my invention may be described as involving the steps ofpreliminarily softening the material to be treated and suspending it inwater, and then causing the water and suspended material to flow througha closed circuit, during which defelting operations are performed upon'it and fresh material is continuously introduced into the circulatingstream while pulped material is continuously withdrawn therefrom.

In practicing the method in the treatment of paper, I first reduce thepaper to pieces of relatively small size in any convenient manner andfor this purpose may put the stock througha hammer mill of conventionaldesign. The paper is then softened and placed in a condition suitablefor pulping and for this purpose, I soak the paper in warm water of atemperature of about 160 to 170 F. Preferably, the soaking is carried onin a suitable vat which contains means by which the paper and water maybe mildly agitated and I place in the vat a charge of about 90% to 95%water, 5% to 10% of paper (dry weight) and a small quantity, such as 2%to 3% of the dry weight of the paper, of a mild detergent of any wellknown type. For this purpose, I may use soap, soda ash. potassiumabietate, and other materials well known in the art. The soaking andagitation of the paper is continued for a short time until the paper isthoroughly softened and the detergent well distributed through it.

The purpose of this preliminary treatment is to soften the p per so thatit can be easily operated 1931, Serial No. 572,131

(or. 92 2o) on in subsequent steps of the process and it will beunderstood that the proportions above given are not critical and may bevaried considerably with good results, depending on the character of thepaper stock being treated and the kind of detergent employed. Thetreatment will also be varied, as is well known in the art, when othermaterials than paper are to be defibred. I have found that paper may bepulped in my process by the use of mild detergents and the detergent maybe wholly omitted in some cases, this use of mild chemicals as adetergent preventing injury to the fibres.

In tearing apart and disentangling the fibres of the paper without doinginjury thereto, I take advantage of the inertia of the pieces of papersuspended in the liquid and subject the suspended paper to the impact ofhigh velocity blades. These blades strike the paper at one point whileit is yieldingly held elsewhere by the liquid and the blades tear thepaper apart, releasing the materials usually present therein and freeingand separating the fibres. In order to carry on the process at a rapidoutput rate, I employ a series of sets of blades in a chamber andconstruct the blades so that they both tear apart the material andpropel it forward to the next set of blades. The blades used are of arotary type and since they impart a high rotational velocity of thematerial, it is evident that measures must be taken to prevent loss ofeffectiveness of the succeeding blades in the series by reason of thevelocity of the material supplied to them. I have found it possible toovercome this difiiculty and secure an additional disintegrating actionby converting the rotational movement of the material leaving the firstset of blades into a rectilinear movement, as, for example, byinterposing tator vanes in the chamber between the sets of rotary impactblades. These stator vanes are prefer-,- ably spaced from the blades sothat a shearing action is avoided which would shorten the fibres but asthe material leaves the blades and enters the spaces between the vanes,the direction of its movement is abruptly changed and this, with theinertia of the fluid and paper produces a further disintegrating effect.

The disintegrating operations are carried on continuously and withoutinterruption, and for this purpose I cause the rotary defibring elementsto serve as means forpropelling the material through a closed circuit.At one point in this circuit, the material is collected in a classifyingchamber from which the pulped product is continuously withdrawn. Freshstock tobe leaving the classifying chamber just in front of the exit,being drawn rapidly therefrom by the suction action of thedisintegrating and impelling of the blades.

devices.

I am aware that it has been proposed heretofore to employ rotary impactblades for disintegrating and propelling material to be pulped throughaclosed circuit but in those prior machines with which I am familiar theoperation is carried on by batches, and the blades are relatively longand no attempt is made to convert the rotational movement of thematerial leaving the blades in the rectilinear movement. When such long'blades are employed, a portion of the material is acted on by parts ofthe blades near their axes-of rotation, which parts move at much lowervelocity than the extreme ends The material is,'therefore, notefficiently acted on by such blades. According to my method, I soconfine the circulating stream of material and fluid through a portionof its circuit as to create a thin annular stream into which the ends ofthe blades project. The material in this stream is acted on by bladesmoving with an extremely high velocity, and the rotary movement of thematerial leaving the blades is converted into rectilinear movement, withthe result that the emciency of the pulping action is greatly'increased.

For a better understanding of my method, reference may be had to theaccompanying drawing, in which Fig. 1 illustrates in vertical section amachine suitable for carrying out the method; and 1 Fig. 2-is asectional view .of the machine on the line 22 of Figure 1.

In the drawing, the machine is illustrated as including a standard 10mounted on a suitable base 11, this standard being constructed at itstop to form the bottom 12 of a generally vertical cylindricalclassifying or vortex chamber 13. Projecting upward above the bottom areside walls 14 and mounted on the inner face of the side walls is apartition 15 of generally conical shape having an open top 16. The space1'7 between the outer surface of the partition and the side walls of thecham er serve as a collecting chamber from which pulped material may bedischarged through an outlet 18. The chamber is provided with an exitopeningdeflned by a tubular partition 19 mounted in a neck 20 projectingupwardly from the bottom and extending down from the exit opening is-ahopper 21 terminating in a chamber 22.

A plurality of deflbring chambers or tubes 23 extend radially fromchamber 22 and are in communication therewith. Four such tubes areemployed in the machine illustrated and they are arranged in pairs inupper and lower levels, with the tubes in each level aligned. In alignedtubes is a drive shaft 24 which extends out through gland devicesgenerally designated 25 at the ends of the tubes. Each shaft is mountedin bearings 26 on standards 27 and is provided with a suitable couplingelement 28 by which it can be-connected to a source of power so as to bedriven at a high speed such as 3600 R. P. M.-

Mounted on the shaft within each tube are sets of disintegratingandimpeller blades 29 and these blades terminate close to the inner wall ofliner members 30 mounted in the tube. Between the liner members are setsof stator vanes 31 projecting into thetube, the faces of the vanes lyingradially so that passages are formed be- 1,97v,so7

tween the vanes which extend axially of the tube. The shaft is providedwith collars 32 between the sets of blades and with conical collars 33beyond each of the end sets of blades. These collars serve to reduce theworking space within the tube and confine the material flowing throughthe tube to a thin annular stream into which the tition and in alignmentwith the tubular part1 tion 19.

In the operation of the machine, stock to be pulped is introducedcontinuously through the feed pipe and passes at once into hopper 21 andchamber 22. The material is drawn out of the chamber 22 by the suctionaction of the blades and as the paper suspended in water reaches theblades in the form of a thin annular stream, the high velocity ends ofthe blades strike the paper with a powerful impact. Due to the inertiaof the paper in the water, the blades tear the paper apart, separatingthe fibres and freeing the loading materials. The blades also impart ahigh rotational velocity to the paper and water but this rotationalmovement is converted into recfined by the vanes and the collars on theshafts which the endsof the vanes just clear and the material flowsthrough these passages to the next set of blades. The operationsdescribed are repeated until the material is propelled out of the tubeby the last set of blades and the stream flows with a rapid whirlingmotion through the discharge line and enters the classifying chamberthrough the tangential nozzles.

The material entering the classifying chamber has a rapid whirlingmotion and it moves upward along the side walls of the chamber and thenupwardly and inwardly on the under surface of the inclined partition."Vortical downward flow then occurs with the main current passing out ofthe chamber through the exit to the tubes. In the body of liquid andpaper within the classifying chamber, the larger particles of paper tendto remain in the main stream while the smaller, more completely deflbredpieces are thrown outward by centrifugal action. This action takes placebecause the water opposes the outward flow of the larger, bulkierparticles in the upwardly moving current, and only the smaller particlescan pass through the liquid into the films which are close to thechamber walls. As fresh stock is continually fed to the device, the bodyof fluid in the classifying. chamber' rises higher and higher until itoverflows and, since the overflow is from the periphery of the stream,the material discharged includes the smaller and more'completelydeflbred pieces, while the larger pieces pass down to the tubes forfurther disintegration.

When the machine is in regular operation, the rate at which material isdischarged equals the rate of feed of fresh stock and the character ofthe material discharged depends upon thenumber of times that thematerial is subjected to the disintegrating action. The number ofpassages of the material through the tubes depends onthe ratio of feedof fresh stock to the rate of total flow through all the dispersingtubes so that with a given rate of flow of fresh stock, a pulp ofincreased dispersion may be produced by increasing the rate of flowthrough the tubes or with the tube fiow constant, the freeness of thepulp may be increased by decreasing the rate of supply.

By confining the circulating material in the form of a thin annularstream in the tubes, the defibring blades act with great effectivenessand the defibring action is assisted bythe impact of the materialleaving the blades upon the sides of the stator vanes and by the wallfriction in the tube and discharge line. Ordinarily the stator vaneswill be spaced from the edges of the blades so as to prevent a shearingaction which would shorten the fibres but with some materials it may bedesirable to take advantage of this shearing action to increase thespeed of pulping. In that event, the stator vanes will clear the edgesof the blades by only a small amount. Also, in some cases, it may bedesirable to omit the stator vanes entirely. In that case, it isdesirable to construct the blades of the several sets so that they havean increasing pitch in the direction of movement of the material. Whenblades of that type are employed, it is possible to maintain theeffectiveness of the later blades in the series in spite of therotational veocity imparted to the material by the preceding blades.

I contemplate that other devices than that described may be employed forthe practice of my method but in all machines in which the principles ofmy method are carried on, the material will be constantly circulatedwith fresh material continuously added and pulp continuously withdrawn.Also, I find it highly advantageous to confine the material in thedefibring region to the form of a thin annular stream so that thematerials may be acted on only by those portions of the blades which aremoving at the highest angular velocity. In the circuit, it is necessaryto provide a chamber in which material may accumulate and I takeadvantage of this by constructing the chamber so that it efiects aclassifying action as well as serving as a collecting means.

The apparatus disclosed in this application for the practise of the newmethod is similar to that set forth and claimed in the applicantscopending application, Serial No. 572,130, filed October 30, 1931, andthis apparatus, with certain changes, may be employed to practice theprocess set forth and claimed in the applicants copending application,Serial No. 572,132, filed October 30, 1931.

What I claim is:

1. A method of disintegrating a material, which comprises moving thematerial suspended in a fluid through a closed circuit and during a partof the travel of said material confining it so that it has the form of athin annular stream, subjecting the material in said stream to highvelocity impact action and simultaneously imparting rotational movementto the material, continuously withdrawing treated material from thecirculating stream and adding fresh stock to the stream.

2. A method of disintegrating a material, which comprises moving thematerial suspended in a fiuid through a closed circuit and during a partof the travel of said material confining it so that it has the form of athin annular stream, subjecting the material in the annular stream tohigh velocity impact action resisted by the instream leaving the chamberwith a vortical flow,

ertia of the suspended material and imparting rotational movement to thematerial, converting the rotational movement of the material torectilinear movement and. simultaneously subjecting it to impact action,continuously withdrawing treated material from the circulating stream,and continuously adding fresh stock to the stream. 3. A method ofdisintegrating a material, which comprises moving the material suspendedin a fluid through a closed circuit and during a part of the travel ofsaid material confining it in the form of a thin annular stream,subjecting the material in the annular stream to high velocity impactaction resisted by the inertia of the suspended material, said actionbeing repeated at spaced points within said tube and impartingrotational movement to the material, converting the rotational movementof the material to rectilinear movement between adjacent points ofimpact action, continuously withdrawing treated 95 material from saidstream, and continuously adding fresh stock to said stream.

4. A method of producing pulp, which comprises moving fibrous materialsuspended in water through a closed circuit including a classifyingchamber, disintegrating the material during its movement outside thechamber, subjecting the material in said chamber to centrifugal andvortex actions to efiect discharge of pulped material of selectedcharacteristics from the circulating stream, and adding fresh stock tothe circulating stream.

5. A method of producing pulp which comprises moving fibrous materialsuspended in water through a closed circuit including a classifyingchamber, disintegrating the material during its movement outside thechamber, introducing thematerial into the chamber near the bottomthereof and in such manner as to produce an upwardly moving streamhaving an inward spiral 115 movement, withdrawing pulped material fromthe stream near its periphery, and adding fresh stock. to the stream.

6. A method of producing pulp which comprises moving fibrous materialsuspended in wa- 120 ter through a closed circuit including aclassifying chamber, disintegrating the material during its movementoutside the chamber, introducing the material from the disintegratingoperation into the chamber near the bottom thereof 125 and insuch manneras to produce an upwardly' moving stream having an inward spiralmovement, withdrawing pulped material from the stream near the uppersurface thereof, and adding fresh stock to the circulating material.

7. A method of producing pulp which. comprises moving fibrous materialsuspended in water through a closed circuit including a classify ingchamber, disintegrating the material during its movement outside thechamber,introducing the material from the disintegrating operation intothe chamber near the bottom thereof in such manner as to produce anupwardly moving stream having an inward spiral movement, saidwithdrawing pulped material from said stream near the periphery thereof,and adding fresh stock to the circulating material.

8. A method of producing pulp which com-'- prises moving fibrousmaterial suspended in water through a closed circuit including aclassifying chamber, disintegrating the material during its movementoutside the chamber, intro- .iucing the material from the disintegratingoperation into the chamber near the bottom there- 150 flow within saidtube and relatively low velocity high volume flow in another part of thecircuit, subjecting the material to disintegrating operations in thehigh velocity portion of the circuit, and continuously withdrawingtreated material from the low velocity portion of the circuit and addingfresh stock thereto.

10. A method of producing pulp from paper which comprises suspending thepaper in water containing a detergent, moving the paper and waterthrough a closed circuit, disintegrating the paper to free the fibresduring the circulating movement, continuously withdrawing water and ;lpfrom the circulating stream, andcontinuously adding fresh stock to thestream.

11. A method of producing pulp of selected characteristics-from fibrousmaterial which comprises moving the material suspended in waterthrough aclosed circuit and during a part of the travel of said materialconfining it in the form of a thin annular stream within atube,disintegrating the material by subjecting it to high velocity impactaction while it is passing through said tube, continuously withdrawingthe pulped material from the circulating stream and adding fresh stockto the stream at the same rate, and varying the rate of movement of thematerial through the circuit and thereby controlling the number of timesthe material will be subjected to disintegrating operations'in order tocontrol the characteristics of the material withdrawn from the stream.

12. A method of producing pulp of specified characteristics from fibrousmaterial, which comprises creating and confining within a tube a thinannular high-velocity stream of material suspended in water,disintegrating the material during its movement through said tube,temporarily storing the disintegrated material and water delivered bysaid stream, continuously withdrawing the pulped material and water fromsaid store, continuously adding fresh material suspended in water tosaid store, the rate of feed and the rate of withdrawal being the same,continuously supplying water and material from said store to saidstream, and regulating the character of the pulped material dischargedby controlling the ratio between the rate of feed and the rate ofmovement of the material in said stream.

13. A method of disintegrating a material which comprises moving thematerial suspended in a fluid through a closed circuit and during a partof the travel of said material confining it to give it the form of athin annular stream, subjecting the circulating material in said streamto part of the travel of said material confining it so that it has theform of a thin annular stream, subjecting the material in said stream tohigh velocity impact action and simultaneously imparting rotationalmovement to the material, segregating material distintegrated to aselected degree from the remainder oi the circulating material,continuously withdrawing a portion of the segregated material, theremainder returning to circulation, and continuously adding fresh stockto the circulating stream.

. THOMAS ROBINSON.

high velocity impact action resisted by the in-'

